Chapter 13 - Vector Geometry - 13.3 Dot Product and the Angle Between Two Vectors - Exercises - Page 666: 16

The angle between the vectors is acute.

Since $$\langle 0,2,4\rangle \cdot \langle 3,1,0\rangle =0+2+0=2\neq 0$$ then the vectors are not orthogonal. The angle between the vectors is acute since their dot product is positive (positive cosine of the dot product indicates that we are in the 1st quadrant).